The FDA does not currently recommend that Source Plasma donors be tested for antibody to hepatitis C virus (anti-HCV). The reason for this stance are as follows: The presence of anti-HCV in the plasma pool (from which plasma products such as albumin, clotting factors, and immune globulins are manufactured) may contribute to the present safety of certain plasma products, such as Immune Globulin and Immune Globulin Intravenous. Plasma from thousands of donors is pooled for the manufacture of plasma derivatives; because current tests probably do not identify all carriers of HCV, the testing of individual units for anti-HCV is not likely to eliminate hepatitis C virus from the pool. The safety of immune globulin products experimentally manufactured from anti-HCV-depleted plasma pools is being explored in an FDA-industry collaborative study. Plasma from about 3000 anti-HCV negative Source Plasma donors (also negative for HBsAg,-anti-HIV, and meeting certain requirements for ALT level) were pooled. The pool will be fractionated into IV immune globulin. A sample of the unprocessed pooled plasma was infused into two chimpanzees and the intravenous immune globulin preparations will be given to three chimpanzees. The chimps will be examined regularly for evidence of hepatitis C infection. It is anticipated that one or both chimps receiving the unprocessed pooled plasma will become infected because, as mentioned above, current tests probably do not detect all carriers of HCV. If any of the chimps infused with immune globulin (manufactured from anti- HCV negative donations) develop hepatitis C, it would imply that testing for anti-HCV is deleterious to the safety of the product. On the other hand, if none of the chimps receiving intravenous immune globulin develop hepatitis C (and one or both chimps that receive the pooled plasma show evidence of the disease), it would be suggest that screening plasma for anti-HCV will not adversely affect the safety of immune globulins. This study has just commenced and is expected to be completed in about 1/2 years.